The present invention relates generally to wireless communications devices, and particularly to wireless communications devices that employ surface-mountable transducers.
Conventionally, a microphone or microphone circuitry is mounted on a printed circuit board (PCB) contained within a housing of the wireless communications device. Audible sound, such as speech, enters through a hole formed in the housing and propagates to the microphone down an acoustic path. In conventional devices, the acoustic path is formed by a grommet or like device positioned between the microphone and the interior surface of the housing. The grommet acts as a seal that permits audible sound from the exterior of the wireless communications device to propagate to the microphone, while preventing other audible sounds, such as those produced by a speaker in the device, from reaching the microphone and causing undesirable feedback.
Because the grommet defines the acoustic path, it imposes certain design limitations. For example, the grommet has physical dimensions that define a minimum spatial separation between the PCB and the housing. This separation generally hinders efforts to reduce the overall size of wireless communications devices. Further, the acoustic path is perpendicular to a surface of the PCB. Therefore, prior art wireless communications devices position the PCB and the housing such that the microphone, the acoustic path, and the hole in the housing, directly align with each other. Additionally, grommets are usually installed manually during the manufacturing process, which results in increased manufacturing costs that are ultimately passed to the consumer.